We are interested in how bacteria and bacterial products shape the development of subsequent innate and adaptive immune responses with the goal of understanding how these host-microbe interactions influence pathogenesis of infections, autoimmunity, allergy, and cancer. Our recently published work using a novel spore-based vaccine against a murine model of inhalation anthrax has shown that cholera toxin, a mucosal adjuvant and the agent responsible for the diarrhea caused by Vibrio cholera, induces a Th17 response characterized by CD4 T cells that secrete IL-17. In 2010, we have followed up on these studies by further investigating the effect of CT-induced gene products on Th17 regulation. These studies have resulted in insights into the regulation of Th17-related cytokines and their role in protection against infection with bacteria such as Staphylococcus aureus. In addition, we have investigated the effect of microbial exposure on the polarization of T cell differentiation. These studies enhance our understanding of the mechanisms controlling T cell differentiation and identify potential pathways that can be targeted to enhance efficacy of vaccines and therapies against cancer, infectious, and immune-mediated diseases.